<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>el挂载点</title>
</head>

<body id="body">
    {{ message }}
    <h2 id="app" class="app">
        {{ message }}
        <span>{{ message }}</span>
    </h2>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var app = new Vue({
            el:"#body",
            data:{
                message:"黑马程序员"
                }
        })
    </script>
</body>
</html>